I made a quick playtest for a modern tactical war game where the job of the recon units was to make enemy units target-able for longer range units like artillery. The problem is that recon units are not that much useful since besides targeting there is no real fog of war because both player know the location of their opponent's.
So I had an idea during the playtest that gave a different function to recon units. First I reduced the movement and attack range of all units. Most vehicle move 3 hex instead of 5.
Now each unit has a detection radius of 1 hex except recon units which has 2. As before, recon units makes unit target-able for artillery. But the new rule is that a unit cannot move adjacent to another unit and attack it unless it was already detected by another unit
In other word, if you have no recon, the first unit will move adjacent to the target to detect it And the second unit will move in to attack. But if you use a recon unit, since they have a detection range of 2, you could detect multiple units with a single unit allowing more units to attack instead losing units for detection.
The problem is that in my game, I dod not want to flip units fog FOW because it is how I keep track of HP. It's also annoying to play with, else I would need blocks. So all units must be visible.